Tiny Dragon - An Encryption Algorithm for Wireless Sensor Networks

Information security is an essential consideration of any distributed network. However, security primitives that provide encryption and authentication are not always suitable for resource-constrained devices, such as the nodes on a wireless sensor network. Here we present a specification for a symmetric cipher especially designed for a wireless sensor network. We build upon the work of Dawson et. al [3] in their general purpose cipher Dragon and on Lim et al. [6] who provided a Dragon-based authentication component for wireless sensor networks. Dragon´s internal state is quite large and unsuitable for constrained devices, and the authentication component works only for very short messages. We present Tiny Dragon, a cipher that uses an 80-bit key in conjunction with a 34-byte state to provide joint encryption and authentication for messages of any length. Compared to Dragon, Tiny Dragon has a greatly reduced implementation footprint, improved per-bit security and is more suitable for deployment in hardware and software. We provide a short security analysis to provide confidence in the algorithm.